1
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Oliw EH. Thirty years with three-dimensional structures of lipoxygenases. Arch Biochem Biophys 2024; 752:109874. [PMID: 38145834 DOI: 10.1016/j.abb.2023.109874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/17/2023] [Accepted: 12/17/2023] [Indexed: 12/27/2023]
Abstract
The X-ray crystal structures of soybean lipoxygenase (LOX) and rabbit 15-LOX were reported in the 1990s. Subsequent 3D structures demonstrated a conserved U-like shape of the substrate cavities as reviewed here. The 8-LOX:arachidonic acid (AA) complex showed AA bound to the substrate cavity carboxylate-out with C10 at 3.4 Å from the iron metal center. A recent cryo-electron microscopy (EM) analysis of the 12-LOX:AA complex illustrated AA in the same position as in the 8-LOX:AA complex. The 15- and 12-LOX complexes with isoenzyme-specific inhibitors/substrate mimics confirmed the U-fold. 5-LOX oxidizes AA to leukotriene A4, the first step in biosynthesis of mediators of asthma. The X-ray structure showed that the entrance to the substrate cavity was closed to AA by Phe and Tyr residues of a partly unfolded α2-helix. Recent X-ray analysis revealed that soaking with inhibitors shifted the short α2-helix to a long and continuous, which opened the substrate cavity. The α2-helix also adopted two conformations in 15-LOX. 12-LOX dimers consisted of one closed and one open subunit with an elongated α2-helix. 13C-ENDOR-MD computations of the 9-MnLOX:linoleate complex showed carboxylate-out position with C11 placed 3.4 ± 0.1 Å from the catalytic water. 3D structures have provided a solid ground for future research.
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Affiliation(s)
- Ernst H Oliw
- Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE 751 24, Uppsala, Sweden.
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2
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Roigas S, Kakularam KR, Rothe M, Heydeck D, Aparoy P, Kuhn H. Bony Fish Arachidonic Acid 15-Lipoxygenases Exhibit Different Catalytic Properties than Their Mammalian Orthologs, Suggesting Functional Enzyme Evolution during Vertebrate Development. Int J Mol Sci 2023; 24:14154. [PMID: 37762455 PMCID: PMC10531496 DOI: 10.3390/ijms241814154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/05/2023] [Accepted: 09/09/2023] [Indexed: 09/29/2023] Open
Abstract
The human genome involves six functional arachidonic acid lipoxygenase (ALOX) genes and the corresponding enzymes (ALOX15, ALOX15B, ALOX12, ALOX12B, ALOXE3, ALOX5) have been implicated in cell differentiation and in the pathogenesis of inflammatory, hyperproliferative, metabolic, and neurological disorders. In other vertebrates, ALOX-isoforms have also been identified, but they occur less frequently. Since bony fish represent the most abundant subclass of vertebrates, we recently expressed and characterized putative ALOX15 orthologs of three different bony fish species (Nothobranchius furzeri, Pundamilia nyererei, Scleropages formosus). To explore whether these enzymes represent functional equivalents of mammalian ALOX15 orthologs, we here compared a number of structural and functional characteristics of these ALOX-isoforms with those of mammalian enzymes. We found that in contrast to mammalian ALOX15 orthologs, which exhibit a broad substrate specificity, a membrane oxygenase activity, and a special type of dual reaction specificity, the putative bony fish ALOX15 orthologs strongly prefer C20 fatty acids, lack any membrane oxygenase activity and exhibit a different type of dual reaction specificity with arachidonic acid. Moreover, mutagenesis studies indicated that the Triad Concept, which explains the reaction specificity of all mammalian ALOX15 orthologs, is not applicable for the putative bony fish enzymes. The observed functional differences between putative bony fish ALOX15 orthologs and corresponding mammalian enzymes suggest a targeted optimization of the catalytic properties of ALOX15 orthologs during vertebrate development.
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Affiliation(s)
- Sophie Roigas
- Department of Biochemistry, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; (S.R.); (K.R.K.); (D.H.)
| | - Kumar R. Kakularam
- Department of Biochemistry, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; (S.R.); (K.R.K.); (D.H.)
| | - Michael Rothe
- Lipidomix GmbH, Robert-Rössle-Straße 10, 13125 Berlin, Germany;
| | - Dagmar Heydeck
- Department of Biochemistry, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; (S.R.); (K.R.K.); (D.H.)
| | - Polamarasetty Aparoy
- Department of Humanities and Sciences, Indian Institute of Petroleum and Energy, Visakhapatnam 530003, India;
| | - Hartmut Kuhn
- Department of Biochemistry, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; (S.R.); (K.R.K.); (D.H.)
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3
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Noguchi S, Tallman KA, Porter NA, Stec DF, Calcutt MW, Boeglin WE, Brash AR. Evaluation of ω-alkynyl-labeled linoleic and arachidonic acids as substrates for recombinant lipoxygenase pathway enzymes. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159360. [PMID: 37336389 PMCID: PMC10528070 DOI: 10.1016/j.bbalip.2023.159360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/02/2023] [Accepted: 06/11/2023] [Indexed: 06/21/2023]
Abstract
ω-Alkynyl-fatty acids can be used as probes for covalent binding to intracellular macromolecules. To inform future in vivo studies, we determined the rates of reaction of ω-alkynyl-labeled linoleate with recombinant enzymes of the skin 12R-lipoxygenase (12R-LOX) pathway involved in epidermal barrier formation (12R-LOX, epidermal lipoxygenase-3 (eLOX3), and SDR9C7). We also examined the reactivity of ω-alkynyl-arachidonic acid with representative lipoxygenase enzymes employing either "carboxyl end-first" substrate binding (5S-LOX) or "tail-first" (platelet-type 12S-LOX). ω-Alkynyl-linoleic acid was oxygenated by 12R-LOX at 62 ± 9 % of the rate compared to linoleic acid, the alkynyl-9R-HPODE product was isomerized by eLOX3 at only 43 ± 1 % of the natural substrate, whereas its epoxy alcohol product was converted to epoxy ketone linoleic by an NADH-dependent dehydrogenase (SDR9C7) with 91 ± 1 % efficiency. The results suggest the optimal approach will be application of the 12R-LOX/eLOX3-derived epoxyalcohol, which should be most efficiently incorporated into the pathway and allow subsequent analysis of covalent binding to epidermal proteins. Regarding the orientation of substrate binding in LOX catalysis, our results and previous reports suggest the ω-alkynyl group has a stronger inhibitory effect on tail-first binding, as might be expected. Beyond slowing the reaction, however, we found that the tail-first binding and transformation of ω-alkynyl-arachidonic acid by platelet-type 12S-LOX results in almost complete enzyme inactivation, possibly due to reactive intermediates blocking the enzyme active site. Overall, the results reinforce the conclusion that ω-alkynyl-fatty acids are suitable for selected applications after appropriate reactivity is established.
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Affiliation(s)
- Saori Noguchi
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, United States of America
| | - Keri A Tallman
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - Ned A Porter
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - Donald F Stec
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - M Wade Calcutt
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, United States of America
| | - William E Boeglin
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, United States of America
| | - Alan R Brash
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, United States of America.
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4
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Smirnova EO, Egorova AM, Lantsova NV, Chechetkin IR, Toporkova YY, Grechkin AN. Recombinant Soybean Lipoxygenase 2 (GmLOX2) Acts Primarily as a ω6( S)-Lipoxygenase. Curr Issues Mol Biol 2023; 45:6283-6295. [PMID: 37623215 PMCID: PMC10452975 DOI: 10.3390/cimb45080396] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/26/2023] Open
Abstract
The lipoxygenase (LOX) cascade is a source of bioactive oxylipins that play a regulatory role in plants, animals, and fungi. Soybean (Glycine max (L.) Merr.) LOXs are the classical models for LOX research. Progress in genomics has uncovered a large diversity of GmLOX isoenzymes. Most of them await biochemical investigations. The catalytic properties of recombinant soybean LOX2 (GmLOX2) are described in the present work. The GmLOX2 gene has been cloned before, but only for nucleotide sequencing, while the recombinant protein was not prepared and studied. In the present work, the recombinant GmLOX2 behavior towards linoleic, α-linolenic, eicosatetraenoic (20:4), eicosapentaenoic (20:5), and hexadecatrienoic (16:3) acids was examined. Linoleic acid was a preferred substrate. Oxidation of linoleic acid afforded 94% optically pure (13S)-hydroperoxide and 6% racemic 9-hydroperoxide. GmLOX2 was less active on other substrates but possessed an even higher degree of regio- and stereospecificity. For example, it converted α-linolenic acid into (13S)-hydroperoxide at about 98% yield. GmLOX2 showed similar specificity towards other substrates, producing (15S)-hydroperoxides (with 20:4 and 20:5) or (11S)-hydroperoxide (with 16:3). Thus, the obtained data demonstrate that soybean GmLOX2 is a specific (13S)-LOX. Overall, the catalytic properties of GmLOX2 are quite similar to those of GmLOX1, but pH is optimum.
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Affiliation(s)
- Elena O. Smirnova
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, P.O. Box 261, 420111 Kazan, Russia; (A.M.E.); (N.V.L.); (I.R.C.)
| | | | | | | | | | - Alexander N. Grechkin
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, P.O. Box 261, 420111 Kazan, Russia; (A.M.E.); (N.V.L.); (I.R.C.)
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5
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Sharma A, Whittington C, Jabed M, Hill SG, Kostenko A, Yu T, Li P, Doan PE, Hoffman BM, Offenbacher AR. 13C Electron Nuclear Double Resonance Spectroscopy-Guided Molecular Dynamics Computations Reveal the Structure of the Enzyme-Substrate Complex of an Active, N-Linked Glycosylated Lipoxygenase. Biochemistry 2023; 62:1531-1543. [PMID: 37115010 PMCID: PMC10704959 DOI: 10.1021/acs.biochem.3c00119] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Lipoxygenase (LOX) enzymes produce important cell-signaling mediators, yet attempts to capture and characterize LOX-substrate complexes by X-ray co-crystallography are commonly unsuccessful, requiring development of alternative structural methods. We previously reported the structure of the complex of soybean lipoxygenase, SLO, with substrate linoleic acid (LA), as visualized through the integration of 13C/1H electron nuclear double resonance (ENDOR) spectroscopy and molecular dynamics (MD) computations. However, this required substitution of the catalytic mononuclear, nonheme iron by the structurally faithful, yet inactive Mn2+ ion as a spin probe. Unlike canonical Fe-LOXs from plants and animals, LOXs from pathogenic fungi contain active mononuclear Mn2+ metallocenters. Here, we report the ground-state active-site structure of the native, fully glycosylated fungal LOX from rice blast pathogen Magnaporthe oryzae, MoLOX complexed with LA, as obtained through the 13C/1H ENDOR-guided MD approach. The catalytically important distance between the hydrogen donor, carbon-11 (C11), and the acceptor, Mn-bound oxygen, (donor-acceptor distance, DAD) for the MoLOX-LA complex derived in this fashion is 3.4 ± 0.1 Å. The difference of the MoLOX-LA DAD from that of the SLO-LA complex, 3.1 ± 0.1 Å, is functionally important, although is only 0.3 Å, despite the MoLOX complex having a Mn-C11 distance of 5.4 Å and a "carboxylate-out" substrate-binding orientation, whereas the SLO complex has a 4.9 Å Mn-C11 distance and a "carboxylate-in" substrate orientation. The results provide structural insights into reactivity differences across the LOX family, give a foundation for guiding development of MoLOX inhibitors, and highlight the robustness of the ENDOR-guided MD approach to describe LOX-substrate structures.
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Affiliation(s)
- Ajay Sharma
- Department of Chemistry, Northwestern University, Evanston, IL 60208, United States
| | - Chris Whittington
- Department of Chemistry, East Carolina University, Greenville, NC 27858, United States
| | - Mohammed Jabed
- Department of Chemistry, University of North Dakota, Grand Forks, ND 58202, United States
| | - S. Gage Hill
- Department of Chemistry, East Carolina University, Greenville, NC 27858, United States
| | - Anastasiia Kostenko
- Department of Chemistry, East Carolina University, Greenville, NC 27858, United States
| | - Tao Yu
- Department of Chemistry, University of North Dakota, Grand Forks, ND 58202, United States
| | - Pengfei Li
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL 60660, United States
| | - Peter E. Doan
- Department of Chemistry, Northwestern University, Evanston, IL 60208, United States
| | - Brian M. Hoffman
- Department of Chemistry, Northwestern University, Evanston, IL 60208, United States
| | - Adam R. Offenbacher
- Department of Chemistry, East Carolina University, Greenville, NC 27858, United States
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6
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Gagestein B, von Hegedus JH, Kwekkeboom JC, Heijink M, Blomberg N, van der Wel T, Florea BI, van den Elst H, Wals K, Overkleeft HS, Giera M, Toes REM, Ioan-Facsinay A, van der Stelt M. Comparative Photoaffinity Profiling of Omega-3 Signaling Lipid Probes Reveals Prostaglandin Reductase 1 as a Metabolic Hub in Human Macrophages. J Am Chem Soc 2022; 144:18938-18947. [PMID: 36197299 PMCID: PMC9585591 DOI: 10.1021/jacs.2c06827] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
The fish oil constituent
docosahexaenoic acid (DHA, 22:6
n-3) is
a signaling lipid with anti-inflammatory properties. The molecular
mechanisms underlying the biological effect of DHA are poorly understood.
Here, we report the design, synthesis, and application of a complementary
pair of bio-orthogonal, photoreactive probes based on the polyunsaturated
scaffold DHA and its oxidative metabolite 17-hydroxydocosahexaenoic
acid (17-HDHA). In these probes, an alkyne serves as a handle to introduce
a fluorescent reporter group or a biotin-affinity tag via copper(I)-catalyzed
azide-alkyne cycloaddition. This pair of chemical probes was used
to map specific targets of the omega-3 signaling lipids in primary
human macrophages. Prostaglandin reductase 1 (PTGR1) was identified
as an interaction partner that metabolizes 17-oxo-DHA, an oxidative
metabolite of 17-HDHA. 17-oxo-DHA reduced the formation of pro-inflammatory
lipids 5-HETE and LTB4 in human macrophages and neutrophils. Our results
demonstrate the potential of comparative photoaffinity protein profiling
for the discovery of metabolic enzymes of bioactive lipids and highlight
the power of chemical proteomics to uncover new biological insights.
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Affiliation(s)
- Berend Gagestein
- Department of Molecular Physiology, Leiden Institute of Chemistry, Leiden University and Oncode Institute, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Johannes H von Hegedus
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Joanneke C Kwekkeboom
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Marieke Heijink
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Niek Blomberg
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Tom van der Wel
- Department of Molecular Physiology, Leiden Institute of Chemistry, Leiden University and Oncode Institute, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Bogdan I Florea
- Bio-Organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Hans van den Elst
- Bio-Organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Kim Wals
- Department of Molecular Physiology, Leiden Institute of Chemistry, Leiden University and Oncode Institute, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Herman S Overkleeft
- Bio-Organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Martin Giera
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - René E M Toes
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Andreea Ioan-Facsinay
- Department of Rheumatology, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Mario van der Stelt
- Department of Molecular Physiology, Leiden Institute of Chemistry, Leiden University and Oncode Institute, Einsteinweg 55, Leiden 2333 CC, The Netherlands
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Nikolaiczyk V, Kirschning A, Díaz E. Lipoxygenase‐catalysed co‐oxidation for sustained production of oxyfunctionalized terpenoids. FLAVOUR FRAG J 2022. [DOI: 10.1002/ffj.3700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Vanessa Nikolaiczyk
- Institute of Organic Chemistry Leibniz University Hannover Hannover Germany
- Symrise AG Holzminden Germany
| | - Andreas Kirschning
- Institute of Organic Chemistry Leibniz University Hannover Hannover Germany
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8
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Zhuravlev A, Golovanov A, Toporkov V, Kuhn H, Ivanov I. Functionalized Homologues and Positional Isomers of Rabbit 15-Lipoxygenase RS75091 Inhibitor. Med Chem 2021; 18:406-416. [PMID: 34097594 DOI: 10.2174/1573406417666210604112009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 03/12/2021] [Accepted: 04/05/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND RS75091 is a cinnamic acid derivative that has been used for the crystallization of the rabbit ALOX15-inhibitor complex. The atomic coordinates of the resolved ALOX15-inhibitor complex were later used to define the binding sites of other mammalian lipoxygenase orthologs, for which no direct structural data with ligand has been reported so far. INTRODUCTION The putative binding pocket of the human ALOX5 was reconstructed on the basis of its structural alignment with rabbit ALOX15-RS75091 inhibitor. However, considering the possible conformational changes the enzyme may undergo in solution, it remains unclear whether the existing models adequately mirror the architecture of the ALOX5 active site. METHODS In this study, we prepared a series of RS75091 derivatives using a Sonogashira coupling reaction of regioisomeric bromocinnamates with protected acetylenic alcohols and tested their inhibitory properties on rabbit ALOX15. RESULTS A bulky pentafluorophenyl moiety linked to either ortho- or metha-ethynylcinnamates via aliphatic spacer does not significantly impair the inhibitory properties of RS75091. CONCLUSION Hydroxylated 2- and 3-alkynylcinnamates may be suitable candidates for incorporation of an aromatic linker group like tetrafluorophenylazides for photoaffinity labeling assays.
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Affiliation(s)
- Alexander Zhuravlev
- Lomonosov Institute of Fine Chemical Technologies, MIREA - Russian Technological University, Vernadskogo pr. 86, 119571 Moscow. Russian Federation
| | - Alexey Golovanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA - Russian Technological University, Vernadskogo pr. 86, 119571 Moscow. Russian Federation
| | - Valery Toporkov
- Lomonosov Institute of Fine Chemical Technologies, MIREA - Russian Technological University, Vernadskogo pr. 86, 119571 Moscow. Russian Federation
| | - Hartmut Kuhn
- Institute of Biochemistry, Charite - University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Charitéplatz 1, D-10117 Berlin. Germany
| | - Igor Ivanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA - Russian Technological University, Vernadskogo pr. 86, 119571 Moscow. Russian Federation
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9
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Structural considerations on lipoxygenase function, inhibition and crosstalk with nitric oxide pathways. Biochimie 2020; 178:170-180. [PMID: 32980463 DOI: 10.1016/j.biochi.2020.09.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 09/10/2020] [Accepted: 09/22/2020] [Indexed: 12/30/2022]
Abstract
Lipoxygenases (LOX) are non-heme iron-containing enzymes that catalyze regio- and stereo-selective dioxygenation of polyunsaturated fatty acids (PUFA). Mammalian LOXs participate in the eicosanoid cascade during the inflammatory response, using preferentially arachidonic acid (AA) as substrate, for the synthesis of leukotrienes (LT) and other oxidized-lipid intermediaries. This review focus on lipoxygenases (LOX) structural and kinetic implications on both catalysis selectivity, as well as the basic and clinical implications of inhibition and interactions with nitric oxide (•NO) and nitroalkenes pathways. During inflammation •NO levels are increasingly favoring the formation of reactive nitrogen species (RNS). •NO may act itself as an inhibitor of LOX-mediated lipid oxidation by reacting with lipid peroxyl radicals. Besides, •NO may act as an O2 competitor in the LOX active site, thus displaying a protective role on lipid-peroxidation. Moreover, RNS such as nitrogen dioxide (•NO2) may react with lipid-derived species formed during LOX reaction, yielding nitroalkenes (NO2FA). NO2FA represents electrophilic compounds that could exert anti-inflammatory actions through the interaction with critical LOX nucleophilic amino acids. We will discuss how nitro-oxidative conditions may limit the availability of common LOX substrates, favoring alternative routes of PUFA metabolization to anti-inflammatory or pro-resolutive pathways.
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10
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Offenbacher AR, Holman TR. Fatty Acid Allosteric Regulation of C-H Activation in Plant and Animal Lipoxygenases. Molecules 2020; 25:molecules25153374. [PMID: 32722330 PMCID: PMC7436259 DOI: 10.3390/molecules25153374] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/18/2020] [Accepted: 07/21/2020] [Indexed: 12/18/2022] Open
Abstract
Lipoxygenases (LOXs) catalyze the (per) oxidation of fatty acids that serve as important mediators for cell signaling and inflammation. These reactions are initiated by a C-H activation step that is allosterically regulated in plant and animal enzymes. LOXs from higher eukaryotes are equipped with an N-terminal PLAT (Polycystin-1, Lipoxygenase, Alpha-Toxin) domain that has been implicated to bind to small molecule allosteric effectors, which in turn modulate substrate specificity and the rate-limiting steps of catalysis. Herein, the kinetic and structural evidence that describes the allosteric regulation of plant and animal lipoxygenase chemistry by fatty acids and their derivatives are summarized.
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Affiliation(s)
- Adam R. Offenbacher
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
- Correspondence:
| | - Theodore R. Holman
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA;
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11
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Freedman C, Tran A, Tourdot BE, Kalyanaraman C, Perry S, Holinstat M, Jacobson MP, Holman TR. Biosynthesis of the Maresin Intermediate, 13S,14S-Epoxy-DHA, by Human 15-Lipoxygenase and 12-Lipoxygenase and Its Regulation through Negative Allosteric Modulators. Biochemistry 2020; 59:1832-1844. [PMID: 32324389 PMCID: PMC7729281 DOI: 10.1021/acs.biochem.0c00233] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Human reticulocyte 15-lipoxygenase-1 (h15-LOX-1 or ALOX15) and platelet 12-lipoxygenase (h12-LOX or ALOX12) catalysis of docosahexaenoic acid (DHA) and the maresin precursor, 14S-hydroperoxy-4Z,7Z,10Z,12E,16Z,19Z-docosahexaenoic acid (14S-HpDHA), were investigated to determine their product profiles and relative rates in the biosynthesis of the key maresin intermediate, 13S,14S-epoxy-4Z,7Z,9E,11E,16Z,19Z-docosahexaenoic acid (13S,14S-epoxy-DHA). Both enzymes converted DHA to 14S-HpDHA, with h12-LOX having a 39-fold greater kcat/KM value (14.0 ± 0.8 s-1 μM-1) than that of h15-LOX-1 (0.36 ± 0.08 s-1 μM-1) and a 1.8-fold greater 14S-HpDHA product selectivity, 81 and 46%, respectively. However, h12-LOX was markedly less effective at producing 13S,14S-epoxy-DHA from 14S-HpDHA than h15-LOX-1, with a 4.6-fold smaller kcat/KM value, 0.0024 ± 0.0002 and 0.11 ± 0.006 s-1 μM-1, respectively. This is the first evidence of h15-LOX-1 to catalyze this reaction and reveals a novel in vitro pathway for maresin biosynthesis. In addition, epoxidation of 14S-HpDHA is negatively regulated through allosteric oxylipin binding to h15-LOX-1 and h12-LOX. For h15-LOX-1, 14S-HpDHA (Kd = 6.0 μM), 12S-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12S-HETE) (Kd = 3.5 μM), and 14S-hydroxy-7Z,10Z,12E,16Z,19Z-docosapentaenoic acid (14S-HDPAω-3) (Kd = 4.0 μM) were shown to decrease 13S,14S-epoxy-DHA production. h12-LOX was also shown to be allosterically regulated by 14S-HpDHA (Kd = 3.5 μM) and 14S-HDPAω-3 (Kd = 4.0 μM); however, 12S-HETE showed no effect, indicating for the first time an allosteric response by h12-LOX. Finally, 14S-HpDHA inhibited platelet aggregation at a submicrololar concentration, which may have implications in the benefits of diets rich in DHA. These in vitro biosynthetic pathways may help guide in vivo maresin biosynthetic investigations and possibly direct therapeutic interventions.
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Affiliation(s)
- Cody Freedman
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Adrianne Tran
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Benjamin E Tourdot
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Chakrapani Kalyanaraman
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, San Francisco, California 94158, United States
| | - Steve Perry
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Michael Holinstat
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Matthew P Jacobson
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, San Francisco, California 94158, United States
| | - Theodore R Holman
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
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12
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Stolterfoht H, Rinnofner C, Winkler M, Pichler H. Recombinant Lipoxygenases and Hydroperoxide Lyases for the Synthesis of Green Leaf Volatiles. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:13367-13392. [PMID: 31591878 DOI: 10.1021/acs.jafc.9b02690] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Green leaf volatiles (GLVs) are mainly C6- and in rare cases also C9-aldehydes, -alcohols, and -esters, which are released by plants in response to biotic or abiotic stresses. These compounds are named for their characteristic smell reminiscent of freshly mowed grass. This review focuses on GLVs and the two major pathway enzymes responsible for their formation: lipoxygenases (LOXs) and fatty acid hydroperoxide lyases (HPLs). LOXs catalyze the peroxidation of unsaturated fatty acids, such as linoleic and α-linolenic acids. Hydroperoxy fatty acids are further converted by HPLs into aldehydes and oxo-acids. In many industrial applications, plant extracts have been used as LOX and HPL sources. However, these processes are limited by low enzyme concentration, stability, and specificity. Alternatively, recombinant enzymes can be used as biocatalysts for GLV synthesis. The increasing number of well-characterized enzymes efficiently expressed by microbial hosts will foster the development of innovative biocatalytic processes for GLV production.
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Affiliation(s)
- Holly Stolterfoht
- Austrian Centre of Industrial Biotechnology , Petersgasse 14 , 8010 Graz , Austria
| | - Claudia Rinnofner
- Austrian Centre of Industrial Biotechnology , Petersgasse 14 , 8010 Graz , Austria
- bisy e.U. , Wetzawinkel 20 , 8200 Hofstaetten , Austria
| | - Margit Winkler
- Austrian Centre of Industrial Biotechnology , Petersgasse 14 , 8010 Graz , Austria
- Institute of Molecular Biotechnology , TU Graz, NAWI Graz, BioTechMed Graz , Petersgasse 14 , 8010 Graz , Austria
| | - Harald Pichler
- Austrian Centre of Industrial Biotechnology , Petersgasse 14 , 8010 Graz , Austria
- Institute of Molecular Biotechnology , TU Graz, NAWI Graz, BioTechMed Graz , Petersgasse 14 , 8010 Graz , Austria
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13
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Gaffney BJ. EPR Spectroscopic Studies of Lipoxygenases. Chem Asian J 2019; 15:42-50. [PMID: 31782616 DOI: 10.1002/asia.201901461] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/27/2019] [Indexed: 11/11/2022]
Abstract
Polyunsaturated fatty acids are sources of diverse natural, and chemically designed products. The enzyme lipoxygenase selectively oxidizes fatty acid acyl chains using controlled free radical chemistry; the products are regio- and stereo-chemically unique hydroperoxides. A conserved structural fold of ≈600 amino acids harbors a long and narrow substrate channel and a well-shielded catalytic iron. Oxygen, a co-substrate, is blocked from the active site until a hydrogen atom is abstracted from substrate bis-allylic carbon, in a non-heme iron redox cycle. EPR spectroscopy of ferric intermediates in lipoxygenase catalysis reveals changes in the metal coordination and leads to a proposal on the nature of the reactive intermediate. Remarkably, free radicals are so well controlled in lipoxygenase chemistry that spin label technology can be applied as well. The current level of understanding of steps in lipoxygenase catalysis, from the EPR perspective, will be reviewed.
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Affiliation(s)
- Betty J Gaffney
- Biological Science, Florida State University, Tallahassee, FL, 32306, USA
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14
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Biocatalytic Synthesis of Natural Green Leaf Volatiles Using the Lipoxygenase Metabolic Pathway. Catalysts 2019. [DOI: 10.3390/catal9100873] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In higher plants, the lipoxygenase enzymatic pathway combined actions of several enzymes to convert lipid substrates into signaling and defense molecules called phytooxylipins including short chain volatile aldehydes, alcohols, and esters, known as green leaf volatiles (GLVs). GLVs are synthesized from C18:2 and C18:3 fatty acids that are oxygenated by lipoxygenase (LOX) to form corresponding hydroperoxides, then the action of hydroperoxide lyase (HPL) produces C6 or C9 aldehydes that can undergo isomerization, dehydrogenation, and esterification. GLVs are commonly used as flavors to confer a fresh green odor of vegetable to perfumes, cosmetics, and food products. Given the increasing demand in these natural flavors, biocatalytic processes using the LOX pathway reactions constitute an interesting application. Vegetable oils, chosen for their lipid profile are converted in natural GLVs with high added value. This review describes the enzymatic reactions of GLVs biosynthesis in the plant, as well as the structural and functional properties of the enzymes involved. The various stages of the biocatalytic production processes are approached from the lipid substrate to the corresponding aldehyde or alcoholic aromas, as well as the biotechnological improvements to enhance the production potential of the enzymatic catalysts.
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15
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Hershelman D, Kahler KM, Price MJ, Lu I, Fu Y, Plumeri PA, Karaisz F, Bassett NF, Findeis PM, Clapp CH. Oxygenation reactions catalyzed by the F557V mutant of soybean lipoxygenase-1: Evidence for two orientations of substrate binding. Arch Biochem Biophys 2019; 674:108082. [PMID: 31473191 DOI: 10.1016/j.abb.2019.108082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/21/2019] [Accepted: 08/23/2019] [Indexed: 01/18/2023]
Abstract
Plant lipoxygenases oxygenate linoleic acid to produce 13(S)-hydroperoxy-9Z,11E-octadecadienoic acid (13(S)-HPOD) or 9-hydroperoxy-10E,12Z-octadecadienoic acid (9(S)-HPOD). The manner in which these enzymes bind substrates and the mechanisms by which they control regiospecificity are uncertain. Hornung et al. (Proc. Natl. Acad. Sci. USA96 (1999) 4192-4197) have identified an important residue, corresponding to phe-557 in soybean lipoxygenase-1 (SBLO-1). These authors proposed that large residues in this position favored binding of linoleate with the carboxylate group near the surface of the enzyme (tail-first binding), resulting in formation of 13(S)-HPOD. They also proposed that smaller residues in this position facilitate binding of linoleate in a head-first manner with its carboxylate group interacting with a conserved arginine residue (arg-707 in SBLO-1), which leads to 9(S)-HPOD. In the present work, we have tested these proposals on SBLO-1. The F557V mutant produced 33% 9-HPOD (S:R = 87:13) from linoleic acid at pH 7.5, compared with 8% for the wild-type enzyme and 12% with the F557V,R707L double mutant. Experiments with 11(S)-deuteriolinoleic acid indicated that the 9(S)-HPOD produced by the F557V mutant involves removal of hydrogen from the pro-R position on C-11 of linoleic acid, as expected if 9(S)-HPOD results from binding in an orientation that is inverted relative to that leading to 13(S)-HPOD. The product distributions obtained by oxygenation of 10Z,13Z-nonadecadienoic acid and arachidonic acid by the F557V mutant support the hypothesis that ω6 oxygenation results from tail-first binding and ω10 oxygenation from head-first binding. The results demonstrate that the regiospecificity of SBLO-1 can be altered by a mutation that facilitates an alternative mode of substrate binding and adds to the body of evidence that 13(S)-HPOD arises from tail-first binding.
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Affiliation(s)
| | - Kirsten M Kahler
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
| | - Morgan J Price
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
| | - Iris Lu
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
| | - Yuhan Fu
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
| | | | - Fred Karaisz
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
| | | | - Peter M Findeis
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
| | - Charles H Clapp
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA.
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16
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Djian B, Hornung E, Ischebeck T, Feussner I. The green microalga Lobosphaera incisa harbours an arachidonate 15S-lipoxygenase. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21 Suppl 1:131-142. [PMID: 30277010 PMCID: PMC6587457 DOI: 10.1111/plb.12920] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/22/2018] [Indexed: 06/08/2023]
Abstract
The green microalga Lobosphaera incisa is an oleaginous eukaryotic alga that is rich in arachidonic acid (20:4). Being rich in this polyunsaturated fatty acid (PUFA), however, makes it sensitive to oxidation. In plants, lipoxygenases (LOXs) are the major enzymes that oxidise these molecules. Here, we describe, to our best knowledge, the first characterisation of a cDNA encoding a LOX (LiLOX) from a green alga. To obtain first insights into its function, we expressed it in E. coli, purified the recombinant enzyme and analysed its enzyme activity. The protein sequence suggests that LiLOX and plastidic LOXs from bryophytes and flowering plants may share a common ancestor. The fact that LiLOX oxidises all PUFAs tested with a consistent oxidation on the carbon n-6, suggests that PUFAs enter the substrate channel through their methyl group first (tail first). Additionally, LiLOX form the fatty acid hydroperoxide in strict S configuration. LiLOX may represent a good model to study plastid LOX, because it is stable after heterologous expression in E. coli and highly active in vitro. Moreover, as the first characterised LOX from green microalgae, it opens the possibility to study endogenous LOX pathways in these organisms.
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Affiliation(s)
- B. Djian
- Department of Plant BiochemistryUniversity of GoettingenAlbrecht‐von‐Haller‐Institute for Plant SciencesGoettingenGermany
| | - E. Hornung
- Department of Plant BiochemistryUniversity of GoettingenAlbrecht‐von‐Haller‐Institute for Plant SciencesGoettingenGermany
| | - T. Ischebeck
- Department of Plant BiochemistryUniversity of GoettingenAlbrecht‐von‐Haller‐Institute for Plant SciencesGoettingenGermany
- Goettingen Metabolomics and Lipidomics LaboratoryUniversity of GoettingenGoettingen Center for Molecular Biosciences (GZMB)GoettingenGermany
| | - I. Feussner
- Department of Plant BiochemistryUniversity of GoettingenAlbrecht‐von‐Haller‐Institute for Plant SciencesGoettingenGermany
- Goettingen Metabolomics and Lipidomics LaboratoryUniversity of GoettingenGoettingen Center for Molecular Biosciences (GZMB)GoettingenGermany
- Department of Plant BiochemistryUniversity of GoettingenGoettingen Center for Molecular Biosciences (GZMB)GoettingenGermany
- Department of Plant BiochemistryUniversity of GoettingenInternational Center for Advanced Studies of Energy Conversion (ICASEC)GoettingenGermany
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17
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Kuhn H, Humeniuk L, Kozlov N, Roigas S, Adel S, Heydeck D. The evolutionary hypothesis of reaction specificity of mammalian ALOX15 orthologs. Prog Lipid Res 2018; 72:55-74. [PMID: 30237084 DOI: 10.1016/j.plipres.2018.09.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/04/2018] [Accepted: 09/13/2018] [Indexed: 02/07/2023]
Affiliation(s)
- Hartmut Kuhn
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Lia Humeniuk
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Nikita Kozlov
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Sophie Roigas
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Susan Adel
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Internal Medicine, Division of Hepathology and Gastroenterology, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Dagmar Heydeck
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany
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18
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Clapp CH, Pachuski J, Bassett NF, Bishop KA, Carter G, Young M, Young T, Fu Y. N-linoleoylamino acids as chiral probes of substrate binding by soybean lipoxygenase-1. Bioorg Chem 2018; 78:170-177. [PMID: 29573638 DOI: 10.1016/j.bioorg.2018.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/25/2018] [Accepted: 03/07/2018] [Indexed: 12/30/2022]
Abstract
Lipoxygenases catalyze the oxygenation of polyunsaturated fatty acids and their derivatives to produce conjugated diene hydroperoxides. Soybean lipoxygenase-1 (SBLO-1) has been the subject of intensive structural and mechanistic study, but the manner in which this enzyme binds substrates is uncertain. Previous studies suggest that the fatty acyl group of the substrate binds in an internal cavity near the catalytic iron with the polar end at the surface of the protein or perhaps external to the protein. To test this model, we have investigated two pairs of enantiomeric N-linoleoylamino acids as substrates for SBLO-1. If the amino acid moiety binds external to the protein, the kinetics and product distribution should show little or no sensitivity to the stereochemical configuration of the amino acid moiety. Consistent with this expectation, N-linoleoyl-l-valine (LLV) and N-linoleoyl-d-valine (LDV) are both good substrates with kcat/Km values that are equal within error and about 40% higher than kcat/Km for linoleic acid. Experiments with N-linoleoyl-l-tryptophan (LLT) and N-linoleoyl-d-tryptophan (LDT) were complicated by the low critical micelle concentrations (CMC = 6-8 μM) of these substances. Below the CMC, LDT is a better substrate by a factor of 2.7. The rates of oxygenation of LDT and LLT continue to rise above the CMC, with modest stereoselectivity in favor of the d enantiomer. With all of the substrates tested, the major product is the 13(S)-hydroperoxide, and the distribution of minor products is not appreciably affected by the configuration of the amino acid moiety. The absence of stereoselectivity with LLV and LDV, the modest magnitude of the stereoselectivity with LLT and LDT, and the ability micellar forms of LLT and LDT to increase the concentration of available substrate are all consistent with the hypothesis that the amino acid moiety binds largely external to SBLO-1 and interacts with it only weakly.
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Affiliation(s)
- Charles H Clapp
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States.
| | - Justin Pachuski
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
| | - Natasha F Bassett
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
| | - Kathleen A Bishop
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
| | - Gillian Carter
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
| | - Megan Young
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
| | - Thomas Young
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
| | - Yuhan Fu
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
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19
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Newie J, Neumann P, Werner M, Mata RA, Ficner R, Feussner I. Lipoxygenase 2 from Cyanothece sp. controls dioxygen insertion by steric shielding and substrate fixation. Sci Rep 2017; 7:2069. [PMID: 28522865 PMCID: PMC5437038 DOI: 10.1038/s41598-017-02153-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 04/06/2017] [Indexed: 01/13/2023] Open
Abstract
The biological function of lipoxygenases depends on the regio and stereo specific formation of fatty acid-derived hydroperoxides and different concepts exist to explain the mechanism that directs dioxygen to a specific carbon atom within the substrate. Here, we report the 1.8 Å resolution crystal structure of a cyanobacterial lipoxygenase that produces bis-allylic hydroperoxides (CspLOX2). Site directed mutagenesis experiments combined with computational approaches reveal that residues around the active site direct dioxygen to a preferred carbon atom and stereo configuration in the substrate fatty acid. Modulating the cavity volume around the pentadiene system of linoleic acid shifted the product formation towards 9S-, 9R-, 13S- or 13R-hydroperoxides in correlation with the site of mutation, thus decreasing the amount of the bis-allylic 11R-hydroperoxide. Decreasing the channel size of a 9R-lipoxygenase (CspLOX1) on the other hand could in turn induce formation of the bis-allylic 11R-hydroperoxide. Together this study suggests that an active site clamp fixing the pentadiene system of the substrate together with steric shielding controls the stereo and regio specific positioning of dioxygen at all positions of the reacting pentadiene system of substrate fatty acids.
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Affiliation(s)
- Julia Newie
- University of Goettingen, Albrecht-von-Haller Institute for Plant Sciences, Department of Plant Biochemistry, Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany
| | - Piotr Neumann
- University of Goettingen, Institute of Microbiology and Genetics, Department of Molecular Structural Biology, Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany
| | - Martin Werner
- University of Goettingen, Institute for Physical Chemistry, Tammannstr. 6, 37077, Goettingen, Germany
| | - Ricardo A Mata
- University of Goettingen, Institute for Physical Chemistry, Tammannstr. 6, 37077, Goettingen, Germany
| | - Ralf Ficner
- University of Goettingen, Institute of Microbiology and Genetics, Department of Molecular Structural Biology, Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany
- University of Goettingen, Goettingen Center for Molecular Biosciences (GZMB), Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany
| | - Ivo Feussner
- University of Goettingen, Albrecht-von-Haller Institute for Plant Sciences, Department of Plant Biochemistry, Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany.
- University of Goettingen, Goettingen Center for Molecular Biosciences (GZMB), Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany.
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20
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Horitani M, Offenbacher AR, Carr CAM, Yu T, Hoeke V, Cutsail GE, Hammes-Schiffer S, Klinman JP, Hoffman BM. 13C ENDOR Spectroscopy of Lipoxygenase-Substrate Complexes Reveals the Structural Basis for C-H Activation by Tunneling. J Am Chem Soc 2017; 139:1984-1997. [PMID: 28121140 PMCID: PMC5322796 DOI: 10.1021/jacs.6b11856] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Indexed: 12/20/2022]
Abstract
In enzymatic C-H activation by hydrogen tunneling, reduced barrier width is important for efficient hydrogen wave function overlap during catalysis. For native enzymes displaying nonadiabatic tunneling, the dominant reactive hydrogen donor-acceptor distance (DAD) is typically ca. 2.7 Å, considerably shorter than normal van der Waals distances. Without a ground state substrate-bound structure for the prototypical nonadiabatic tunneling system, soybean lipoxygenase (SLO), it has remained unclear whether the requisite close tunneling distance occurs through an unusual ground state active site arrangement or by thermally sampling conformational substates. Herein, we introduce Mn2+ as a spin-probe surrogate for the SLO Fe ion; X-ray diffraction shows Mn-SLO is structurally faithful to the native enzyme. 13C ENDOR then reveals the locations of 13C10 and reactive 13C11 of linoleic acid relative to the metal; 1H ENDOR and molecular dynamics simulations of the fully solvated SLO model using ENDOR-derived restraints give additional metrical information. The resulting three-dimensional representation of the SLO active site ground state contains a reactive (a) conformer with hydrogen DAD of ∼3.1 Å, approximately van der Waals contact, plus an inactive (b) conformer with even longer DAD, establishing that stochastic conformational sampling is required to achieve reactive tunneling geometries. Tunneling-impaired SLO variants show increased DADs and variations in substrate positioning and rigidity, confirming previous kinetic and theoretical predictions of such behavior. Overall, this investigation highlights the (i) predictive power of nonadiabatic quantum treatments of proton-coupled electron transfer in SLO and (ii) sensitivity of ENDOR probes to test, detect, and corroborate kinetically predicted trends in active site reactivity and to reveal unexpected features of active site architecture.
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Affiliation(s)
- Masaki Horitani
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Adam R. Offenbacher
- Department of Chemistry and California Institute for Quantitative
Biosciences (QB3), Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
| | - Cody A. Marcus Carr
- Department of Chemistry and California Institute for Quantitative
Biosciences (QB3), Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
| | - Tao Yu
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Veronika Hoeke
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - George E. Cutsail
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Sharon Hammes-Schiffer
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Judith P. Klinman
- Department of Chemistry and California Institute for Quantitative
Biosciences (QB3), Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
| | - Brian M. Hoffman
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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21
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Kalms J, Banthiya S, Galemou Yoga E, Hamberg M, Holzhutter HG, Kuhn H, Scheerer P. The crystal structure of Pseudomonas aeruginosa lipoxygenase Ala420Gly mutant explains the improved oxygen affinity and the altered reaction specificity. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:463-473. [PMID: 28093240 DOI: 10.1016/j.bbalip.2017.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/03/2017] [Accepted: 01/12/2017] [Indexed: 12/30/2022]
Abstract
Secreted LOX from Pseudomonas aeruginosa (PA-LOX) has previously been identified as arachidonic acid 15S-lipoxygenating enzyme. Here we report that the substitution of Ala420Gly in PA-LOX leads to an enzyme variant with pronounced dual specificity favoring arachidonic acid 11R-oxygenation. When compared with other LOX-isoforms the molecular oxygen affinity of wild-type PA-LOX is 1-2 orders of magnitude lower (Km O2 of 0.4mM) but Ala420Gly exchange improved the molecular oxygen affinity (Km O2 of 0.2mM). Experiments with stereo-specifically deuterated linoleic acid indicated that the formation of both 13S- and 9R-HpODE involves abstraction of the proS-hydrogen from C11 of the fatty acid backbone. To explore the structural basis for the observed functional changes (altered specificity, improved molecular oxygen affinity) we solved the crystal structure of the Ala420Gly mutant of PA-LOX at 1.8Å resolution and compared it with the wild-type enzyme. Modeling of fatty acid alignment at the catalytic center suggested that in the wild-type enzyme dioxygen is directed to C15 of arachidonic acid by a protein tunnel, which interconnects the catalytic center with the protein surface. Ala420Gly exchange redirects intra-enzyme O2 diffusion by bifurcating this tunnel so that C11 of arachidonic acid also becomes accessible for O2 insertion.
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Affiliation(s)
- Jacqueline Kalms
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Swathi Banthiya
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Etienne Galemou Yoga
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Mats Hamberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Hermann-Georg Holzhutter
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Hartmut Kuhn
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany.
| | - Patrick Scheerer
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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22
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Gandhi H, O'Reilly K, Gupta MK, Horgan C, O'Leary EM, O'Sullivan TP. Advances in the synthesis of acyclic peroxides. RSC Adv 2017. [DOI: 10.1039/c6ra28489b] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
This review summarises the many developments in the synthesis of acyclic peroxides, with a particular focus on the past 20 years, and seeks to update organic chemists about these new approaches.
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Affiliation(s)
- H. Gandhi
- Department of Chemistry
- University College Cork
- Cork
- Ireland
- Analytical and Biological Chemistry Research Facility
| | - K. O'Reilly
- Department of Chemistry
- University College Cork
- Cork
- Ireland
- Analytical and Biological Chemistry Research Facility
| | - M. K. Gupta
- Department of Chemistry
- University College Cork
- Cork
- Ireland
- Analytical and Biological Chemistry Research Facility
| | - C. Horgan
- Department of Chemistry
- University College Cork
- Cork
- Ireland
| | - E. M. O'Leary
- Department of Chemistry
- University College Cork
- Cork
- Ireland
- Analytical and Biological Chemistry Research Facility
| | - T. P. O'Sullivan
- Department of Chemistry
- University College Cork
- Cork
- Ireland
- Analytical and Biological Chemistry Research Facility
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23
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Programmed chloroplast destruction during leaf senescence involves 13-lipoxygenase (13-LOX). Proc Natl Acad Sci U S A 2016; 113:3383-8. [PMID: 26969728 DOI: 10.1073/pnas.1525747113] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Leaf senescence is the terminal stage in the development of perennial plants. Massive physiological changes occur that lead to the shut down of photosynthesis and a cessation of growth. Leaf senescence involves the selective destruction of the chloroplast as the site of photosynthesis. Here, we show that 13-lipoxygenase (13-LOX) accomplishes a key role in the destruction of chloroplasts in senescing plants and propose a critical role of its NH2-terminal chloroplast transit peptide. The 13-LOX enzyme identified here accumulated in the plastid envelope and catalyzed the dioxygenation of unsaturated membrane fatty acids, leading to a selective destruction of the chloroplast and the release of stromal constituents. Because 13-LOX pathway products comprise compounds involved in insect deterrence and pathogen defense (volatile aldehydes and oxylipins), a mechanism of unmolested nitrogen and carbon relocation is suggested that occurs from leaves to seeds and roots during fall.
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Adel S, Heydeck D, Kuhn H, Ufer C. The lipoxygenase pathway in zebrafish. Expression and characterization of zebrafish ALOX5 and comparison with its human ortholog. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1-11. [DOI: 10.1016/j.bbalip.2015.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/30/2015] [Accepted: 10/04/2015] [Indexed: 01/08/2023]
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25
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Ivanov I, Kuhn H, Heydeck D. Structural and functional biology of arachidonic acid 15-lipoxygenase-1 (ALOX15). Gene 2015; 573:1-32. [PMID: 26216303 PMCID: PMC6728142 DOI: 10.1016/j.gene.2015.07.073] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/26/2015] [Accepted: 07/21/2015] [Indexed: 12/14/2022]
Abstract
Lipoxygenases (LOX) form a family of lipid peroxidizing enzymes, which have been implicated in a number of physiological processes and in the pathogenesis of inflammatory, hyperproliferative and neurodegenerative diseases. They occur in two of the three domains of terrestrial life (bacteria, eucarya) and the human genome involves six functional LOX genes, which encode for six different LOX isoforms. One of these isoforms is ALOX15, which has first been described in rabbits in 1974 as enzyme capable of oxidizing membrane phospholipids during the maturational breakdown of mitochondria in immature red blood cells. During the following decades ALOX15 has extensively been characterized and its biological functions have been studied in a number of cellular in vitro systems as well as in various whole animal disease models. This review is aimed at summarizing the current knowledge on the protein-chemical, molecular biological and enzymatic properties of ALOX15 in various species (human, mouse, rabbit, rat) as well as its implication in cellular physiology and in the pathogenesis of various diseases.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Hartmut Kuhn
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Dagmar Heydeck
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
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26
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Mitra S, Bartlett SG, Newcomer ME. Identification of the Substrate Access Portal of 5-Lipoxygenase. Biochemistry 2015; 54:6333-42. [PMID: 26427761 DOI: 10.1021/acs.biochem.5b00930] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The overproduction of inflammatory lipid mediators derived from arachidonic acid contributes to asthma and cardiovascular diseases, among other pathologies. Consequently, the enzyme that initiates the synthesis of pro-inflammatory leukotrienes, 5-lipoxygenase (5-LOX), is a target for drug design. The crystal structure of 5-LOX revealed a fully encapsulated active site; thus the point of substrate entry is not known. We asked whether a structural motif, a "cork" present in 5-LOX but absent in other mammalian lipoxygenases, might be ejected to allow substrate access. Our results indicate that reduction of cork volume facilitates access to the active site. However, if cork entry into the site is obstructed, enzyme activity is significantly compromised. The results support a model in which the "cork" that shields the active site in the absence of substrate serves as the active site portal, but the "corking" amino acid Phe-177 plays a critical role in providing a fully functional active site. Thus, the more appropriate metaphor for this structural motif is a "twist-and-pour" cap. Additional mutagenesis data are consistent with a role for His-600, deep in the elongated cavity, in positioning the substrate for catalysis.
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Affiliation(s)
- Sunayana Mitra
- Department of Biological Sciences, Louisiana State University , Baton Rouge, Louisiana 70803, United States
| | - Sue G Bartlett
- Department of Biological Sciences, Louisiana State University , Baton Rouge, Louisiana 70803, United States
| | - Marcia E Newcomer
- Department of Biological Sciences, Louisiana State University , Baton Rouge, Louisiana 70803, United States
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27
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Newcomer ME, Brash AR. The structural basis for specificity in lipoxygenase catalysis. Protein Sci 2015; 24:298-309. [PMID: 25524168 DOI: 10.1002/pro.2626] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/12/2014] [Indexed: 01/02/2023]
Abstract
Many intriguing facets of lipoxygenase (LOX) catalysis are open to a detailed structural analysis. Polyunsaturated fatty acids with two to six double bonds are oxygenated precisely on a particular carbon, typically forming a single chiral fatty acid hydroperoxide product. Molecular oxygen is not bound or liganded during catalysis, yet it is directed precisely to one position and one stereo configuration on the reacting fatty acid. The transformations proceed upon exposure of substrate to enzyme in the presence of O2 (RH + O2 → ROOH), so it has proved challenging to capture the precise mode of substrate binding in the LOX active site. Beginning with crystal structures with bound inhibitors or surrogate substrates, and most recently arachidonic acid bound under anaerobic conditions, a picture is consolidating of catalysis in a U-shaped fatty acid binding channel in which individual LOX enzymes use distinct amino acids to control the head-to-tail orientation of the fatty acid and register of the selected pentadiene opposite the non-heme iron, suitably positioned for the initial stereoselective hydrogen abstraction and subsequent reaction with O2 . Drawing on the crystal structures available currently, this review features the roles of the N-terminal β-barrel (C2-like, or PLAT domain) in substrate acquisition and sensitivity to cellular calcium, and the α-helical catalytic domain in fatty acid binding and reactions with O2 that produce hydroperoxide products with regio and stereospecificity. LOX structures combine to explain how similar enzymes with conserved catalytic machinery differ in product, but not substrate, specificities.
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Affiliation(s)
- Marcia E Newcomer
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, 70803
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28
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Schiller D, Contreras C, Vogt J, Dunemann F, Defilippi BG, Beaudry R, Schwab W. A dual positional specific lipoxygenase functions in the generation of flavor compounds during climacteric ripening of apple. HORTICULTURE RESEARCH 2015; 2:15003. [PMID: 26504564 PMCID: PMC4595979 DOI: 10.1038/hortres.2015.3] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/09/2015] [Accepted: 01/21/2015] [Indexed: 05/21/2023]
Abstract
Lipoxygenase (LOX) is an important contributor to the formation of aroma-active C6 aldehydes in apple (Malus × domestica) fruit upon tissue disruption but little is known about its role in autonomously produced aroma volatiles from intact tissue. We explored the expression of 22 putative LOX genes in apple throughout ripening, but only six LOXs were expressed in a ripening-dependent manner. Recombinant LOX1:Md:1a, LOX1:Md:1c, LOX2:Md:2a and LOX2:Md:2b proteins showed 13/9-LOX, 9-LOX, 13/9-LOX and 13-LOX activity with linoleic acid, respectively. While products of LOX1:Md:1c and LOX2:Md:2b were S-configured, LOX1:Md:1a and LOX2:Md:2a formed 13(R)-hydroperoxides as major products. Site-directed mutagenesis of Gly567 to an alanine converted the dual positional specific LOX1:Md:1a to an enzyme with a high specificity for 9(S)-hydroperoxide formation. The high expression level of the corresponding MdLOX1a gene in stored apple fruit, the genetic association with a quantitative trait locus for fruit ester and the remarkable agreement in regio- and stereoselectivity of the LOX1:Md:1a reaction with the overall LOX activity found in mature apple fruits, suggest a major physiological function of LOX1:Md:1a during climacteric ripening of apples. While LOX1:Md:1c, LOX2:Md:2a and LOX2:Md:2b may contribute to aldehyde production in immature fruit upon cell disruption our results furnish additional evidence that LOX1:Md:1a probably regulates the availability of precursors for ester production in intact fruit tissue.
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Affiliation(s)
- Doreen Schiller
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, D-85354 Freising, Germany
| | - Carolina Contreras
- Michigan State University, Department of Horticulture, 1066 Bogue Street, East Lansing, MI 48824, USA
| | - Jörg Vogt
- Julius Kühn-Institut (JKI) – Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Fruit Crops, Pillnitzer Platz 3a, D-01326 Dresden, Germany
| | - Frank Dunemann
- Julius Kühn-Institut (JKI) – Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Horticultural Crops, Erwin-Baur-Str. 27, D-06484 Quedlinburg, Germany
| | | | - Randolph Beaudry
- Michigan State University, Department of Horticulture, 1066 Bogue Street, East Lansing, MI 48824, USA
| | - Wilfried Schwab
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, D-85354 Freising, Germany
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29
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Gaffney BJ. Connecting lipoxygenase function to structure by electron paramagnetic resonance. Acc Chem Res 2014; 47:3588-95. [PMID: 25341190 PMCID: PMC4270396 DOI: 10.1021/ar500290r] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Indexed: 01/09/2023]
Abstract
CONSPECTUS: Lipoxygenase enzymes insert oxygen in a polyunsaturated lipid, yielding a hydroperoxide product. When the acyl chain is arachidonate, with three cis-pentadiene units, 12 positionally and stereochemically different products might result. The plant lipids, linoleate and linolenate, have, respectively, four and eight potential oxygen insertion sites. The puzzle of how specificity is achieved in these reactions grows as more and more protein structures confirm the conservation of a lipoxygenase protein fold in plants, animals, and bacteria. Lipoxygenases are large enough (60-100 kDa) that they provide a protein shell completely surrounding an active site cavity that has the shape of a long acyl chain and contains a catalytic metal (usually iron). This Account summarizes electron paramagnetic resonance (EPR) spectroscopic, and other, experiments designed to bridge the gap between lipid-lipoxygenase interactions in solution and crystal structures. Experiments with spin-labeled lipids give a picture of bound lipids tethered to protein by an acyl chain, but with a polar end emerging from the cavity to solvent exposure, where the headgroup is highly flexible. The location of a spin on the polar end of a lysolecithin was determined by pulsed, dipolar EPR measurements, by representing the protein structure as a five-point grid of spin-labels with coordinates derived from 10 distance determinations between spin pairs. Distances from the lipid spin to each grid site completed a six-point representation of the enzyme with a bound lipid. Insight into the dynamics that allow substrate/product to enter/exit the cavity was obtained with a different set of spin-labeled protein mutants. Once substrate enters the cavity, the rate-limiting step of catalysis involves redox cycling at the metal center. Here, a mononuclear iron cycles between ferric and ferrous (high-spin) forms. Two helices provide pairs of side-chain ligands to the iron, resulting in characteristic EPR signals. Quantitative comparison of EPR spectra of plant and bacterial lipoxygenases has suggested conservation of a unique geometry of lipoxygenase iron centers. High frequency (94 GHz) EPR is consistent with a similar metal center in a manganese version of lipoxygenase. Overall, established and emerging EPR experiments have been developed and applied to the lipoxygenase family of enzymes to elucidate changes in the solution structures that are related to function.
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Affiliation(s)
- Betty J. Gaffney
- Department
of Biological
Science, Florida State University, Tallahassee, Florida 32306-4295, United States
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30
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Solvent-induced 7R-dioxygenase activity of soybean 15-lipoxygenase-1 in the formation of omega-3 DPA-derived resolvin analogs. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.molcatb.2014.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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31
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Bradshaw M, Gaffney BJ. Fluctuations of an exposed π-helix involved in lipoxygenase substrate recognition. Biochemistry 2014; 53:5102-10. [PMID: 25036469 PMCID: PMC4131896 DOI: 10.1021/bi500768c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 07/16/2014] [Indexed: 01/14/2023]
Abstract
The second helix in lipoxygenases adapts to permit substrate access to the active site, but details of this process are varied and poorly understood. We therefore examined the dynamics of helix 2 in solutions of spin-labeled soybean lipoxygenase-1 and spin relaxation at 60 K of the spin-labels by catalytic iron. Helix 2 in soybean lipoxygenase structures is surface-exposed and contains one turn of π-helix, centrally located. A site-directed spin-label scan of 18 of the 21 helix 2 residues, and electron paramagnetic resonance, showed that the π-helical segment became unusually mobile, on a nanosecond time scale, under conditions favoring substrate binding (pH 9 and lipid addition), while segments before and after had relatively unchanged dynamics. Backbone dynamics of residues in the π-helical segment appeared to be correlated, at pH 9. Samples also were frozen to examine the polarity and proticity of the local environments, the effect of the local environment on intrinsic relaxation, and dipolar relaxation by two symmetries of catalytic iron. The average hyperfine tensor component, Azz, of four π-helix residues decreased by 1.75 G, with an increase in pH from 7 to 9, while it remained unaffected for nearby buried residues. Power saturation data suggested the change in polarity specific to the π-helix altered the intrinsic relaxation rates. Different symmetries of iron contributed to distance-dependent magnetic relaxation. We interpret these data to mean that a π-helix in the second helix of plant lipoxygenases is highly dynamic and is the site where lipid chains penetrate to inner helices that outline the substrate pocket.
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Affiliation(s)
- Miles
D. Bradshaw
- Department
of Biological
Science, Florida State University, Tallahassee, Florida 32306-4295, United States
| | - Betty J. Gaffney
- Department
of Biological
Science, Florida State University, Tallahassee, Florida 32306-4295, United States
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32
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Ramirez AM, Yang T, Bouwmeester HJ, Jongsma MA. A trichome-specific linoleate lipoxygenase expressed during pyrethrin biosynthesis in pyrethrum. Lipids 2013; 48:1005-15. [PMID: 23893337 DOI: 10.1007/s11745-013-3815-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 07/03/2013] [Indexed: 10/26/2022]
Abstract
The lipid precursor alcohols of pyrethrins-jasmolone, pyrethrolone and cinerolone-have been proposed as sharing parts of the oxylipin pathway with jasmonic acid. This implies that one of the first committed steps of pyrethrin biosynthesis is catalyzed by a lipoxygenase, catalyzing the hydroperoxidation of linolenic acid at position 13. Previously, we showed that the expression and activity of chrysanthemyl diphosphate synthase (TcCDS), the enzyme catalyzing the first committed step in the biosynthesis of the acid moiety of pyrethrins, is trichome-specific and developmentally regulated in flowers. In the present study we characterized the expression pattern of 25 lipoxygenase EST contigs, and subsequently carried out the molecular cloning of two pyrethrum lipoxygenases, TcLOX1 and TcLOX2, that have a similar pattern to TcCDS. Only recombinant TcLOX1 catalyzed the peroxidation of the linolenic acid substrate. Just as TcCDS, TcLOX1, are exclusively expressed in trichomes. Phylogenetic analysis showed that the enzyme shared the highest homology with chloroplast-localized 13-type-lipoxygenases that are involved in maintaining basal levels of jasmonate.
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Affiliation(s)
- Aldana M Ramirez
- Plant Research International, Wageningen University and Research Centre, Wageningen, The Netherlands
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33
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Dobson EP, Barrow CJ, Kralovec JA, Adcock JL. Controlled formation of mono- and dihydroxy-resolvins from EPA and DHA using soybean 15-lipoxygenase. J Lipid Res 2013; 54:1439-47. [PMID: 23471029 PMCID: PMC3622336 DOI: 10.1194/jlr.m036186] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 02/26/2013] [Indexed: 12/20/2022] Open
Abstract
Resolvins and protectins are important anti-inflammatory and pro-resolution compounds derived from the enzymatic oxidation of omega-3 fatty acids all-cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and all-cis-4,7,10,13,16,19-docosahexaenoic acid (DHA). We have developed a simple, controlled method to synthesize an array of resolvin and protectin analogs from fatty acid starting materials using soybean 15-lipoxygenase. The conditions were optimized for the production of both mono- and dihydroxy derivatives, with enzyme concentration and pH found to have a significant effect on the reaction products. The methods were applied to five biologically important omega-3 and omega-6 fatty acid substrates. Mono- and dihydroxy compounds were successfully synthesized from all substrates and the products were characterized by normal phase (NP) HPLC, GC-MS, TOF-MS, UV-visible (UV-vis) spectroscopy, and NMR spectroscopy. The methods could be further applied to any polyunsaturated fatty acids containing the cis-1,4,7,10-undecatetraene moiety to produce a range of novel compounds with potential biological activity.
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Affiliation(s)
- Eleanor P. Dobson
- Centre for Chemistry and Biotechnology, Deakin University, Geelong, Victoria 3220, Australia; and
| | - Colin J. Barrow
- Centre for Chemistry and Biotechnology, Deakin University, Geelong, Victoria 3220, Australia; and
| | | | - Jacqui L. Adcock
- Centre for Chemistry and Biotechnology, Deakin University, Geelong, Victoria 3220, Australia; and
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34
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Suardíaz R, Masgrau L, Lluch JM, González-Lafont A. An insight into the regiospecificity of linoleic acid peroxidation catalyzed by mammalian 15-lipoxygenases. J Phys Chem B 2013; 117:3747-54. [PMID: 23496802 DOI: 10.1021/jp312747q] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
15-Lipoxygenases (15-LOs) catalyze the peroxidation reaction of linoleic acid (LA) in mammals producing almost exclusively 13-(S)-hydroperoxyoctadecadienoic acid (13-(S)-HPODE). Although several hypotheses have been formulated, the molecular basis of such enzymatic regiospecificity is unclear. We have here combined quantum mechanics/molecular mechanics (QM/MM) calculations with molecular dynamics simulations to analyze the peroxidation mechanism using a complete rabbit 15-LO-1/LA solvated model. C9 and C13 being equivalent for planarity and spin density, the QM/MM potential energy profiles of the O2 addition to those two atoms were calculated. The difference in the potential energy barrier heights is clear enough to justify that O2 selectively attacks C13 giving 13-(S)-HPODE. Oxygenation at C9 is hindered by two steric-shielding residues (Leu597 and Gln548). The calculated free energy profile at 300 K for the O2 addition to C13 confirms that the peroxidation on C13 is a reversible viable process in agreement with experiments. Thus, the subsequent reduction of the peroxyl radical to give the final hydroperoxidated product is expected to give the irreversibility character to the overall process.
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Affiliation(s)
- Reynier Suardíaz
- Departament de Química and ‡Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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35
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Gaffney BJ, Bradshaw MD, Frausto SD, Wu F, Freed JH, Borbat P. Locating a lipid at the portal to the lipoxygenase active site. Biophys J 2012; 103:2134-44. [PMID: 23200047 PMCID: PMC3512035 DOI: 10.1016/j.bpj.2012.10.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 10/01/2012] [Accepted: 10/05/2012] [Indexed: 11/28/2022] Open
Abstract
Lipoxygenase enzymes initiate diverse signaling pathways by specifically directing oxygen to different carbons of arachidonate and other polyunsaturated acyl chains, but structural origins of this specificity have remained unclear. We therefore determined the nature of the lipoxygenase interaction with the polar-end of a paramagnetic lipid by electron paramagnetic resonance spectroscopy. Distances between selected grid points on soybean seed lipoxygenase-1 (SBL1) and a lysolecithin spin-labeled on choline were measured by pulsed (electron) dipolar spectroscopy. The protein grid was designed by structure-based modeling so that five natural side chains were replaced with spin labels. Pairwise distances in 10 doubly spin-labeled mutants were examined by pulsed dipolar spectroscopy, and a fit to the model was optimized. Finally, experimental distances between the lysolecithin spin and each single spin site on SBL1 were also obtained. With these 15 distances, distance geometry localized the polar-end and the spin of the lysolecithin to the region between the two domains in the SBL1 structure, nearest to E236, K260, Q264, and Q544. Mutation of a nearby residue, E256A, relieved the high pH requirement for enzyme activity of SBL1 and allowed lipid binding at pH 7.2. This general approach could be used to locate other flexible molecules in macromolecular complexes.
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Affiliation(s)
- Betty J Gaffney
- Department of Biological Science Department, Florida State University, Tallahassee, FL, USA.
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36
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Applications of stereospecifically-labeled Fatty acids in oxygenase and desaturase biochemistry. Lipids 2011; 47:101-16. [PMID: 21971646 DOI: 10.1007/s11745-011-3612-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 08/30/2011] [Indexed: 10/17/2022]
Abstract
Oxygenation and desaturation reactions are inherently associated with the abstraction of a hydrogen from the fatty acid substrate. Since the first published application in 1965, stereospecific placement of a labeled hydrogen isotope (deuterium or tritium) at the reacting carbons has proven a highly effective strategy for investigating the chemical mechanisms catalyzed by lipoxygenases, hemoprotein fatty acid dioxygenases including cyclooxygenases, cytochromes P450, and also the desaturases and isomerases. This review presents a synopsis of all published studies through 2010 on the synthesis and use of stereospecifically labeled fatty acids (71 references), and highlights some of the mechanistic insights gained by application of stereospecifically labeled fatty acids.
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37
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Jansen C, Hofheinz K, Vogel R, Roffeis J, Anton M, Reddanna P, Kuhn H, Walther M. Stereocontrol of arachidonic acid oxygenation by vertebrate lipoxygenases: newly cloned zebrafish lipoxygenase 1 does not follow the Ala-versus-Gly concept. J Biol Chem 2011; 286:37804-12. [PMID: 21880725 DOI: 10.1074/jbc.m111.259242] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Animal lipoxygenases (LOXs) are classified according to their specificity of arachidonic acid oxygenation, and previous sequence alignments suggested that S-LOXs contain a conserved Ala at a critical position at the active site but R-LOXs carry a Gly instead. Here we cloned, expressed, and characterized a novel LOX isoform from the model vertebrate Danio rerio (zebrafish) that carries a Gly at this critical position, classifying this enzyme as putative arachidonic acid R-LOX. Surprisingly, the almost exclusive arachidonic acid oxygenation product was 12S-H(p)ETE (hydro(pero)xyeicosatetraenoic acid), and extensive mutation around Gly-410 failed to induce R-lipoxygenation. This finding prompted us to explore the importance of the corresponding amino acids in other vertebrate S-LOXs. We found that Ala-to-Gly exchange in human 15-LOX2 and human platelet 12-LOX induced major alterations in the reaction specificity with an increase of specific R-oxygenation products. For mouse 5-LOX and 12/15-LOX from rabbits, men, rhesus monkeys, orangutans, and mice, only minor alterations in the reaction specificity were observed. For these enzymes, S-HETE (hydroxyeicosatetraenoic acid) isomers remained the major oxygenation products, whereas chiral R-HETEs contributed only 10-30% to the total product mixture. Taken together these data indicate that the Ala-versus-Gly concept may not always predict the reaction specificity of vertebrate LOX isoforms.
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Affiliation(s)
- Christian Jansen
- Institute of Biochemistry, University Medicine Berlin-Charité, Monbijoustrasse 2, D-10117 Berlin, Germany
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38
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Identification of putative residues involved in the accessibility of the substrate-binding site of lipoxygenase by site-directed mutagenesis studies. Arch Biochem Biophys 2011; 509:82-9. [DOI: 10.1016/j.abb.2011.02.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 02/03/2011] [Accepted: 02/07/2011] [Indexed: 11/18/2022]
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39
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Chohany LE, Bishop KA, Camic H, Sup SJ, Findeis PM, Clapp CH. Cationic substrates of soybean lipoxygenase-1. Bioorg Chem 2011; 39:94-100. [PMID: 21257189 DOI: 10.1016/j.bioorg.2010.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Revised: 12/20/2010] [Accepted: 12/21/2010] [Indexed: 11/18/2022]
Abstract
Soybean lipoxygenase-1 (SBLO-1) catalyzes the oxygenation of 1,4-dienes to produce conjugated diene hydroperoxides. The best substrates are anions of fatty acids; for example, linoleate is converted to 13(S)-hydroperoxy-9(Z),11(E)-octadecadienoate. The manner in which SBLO-1 binds substrates is uncertain. In the present work, it was found that SBLO-1 will oxygenate linoleyltrimethylammonium ion (LTMA) to give primarily13(S)-hydroperoxy-9(Z),11(E)-octadecadienyltrimethylammonium ion. The rate of this process is about the same at pH 7 and pH 9 and is about 30% of the rate observed with linoleate at pH 9. At pH 7, SBLO-1 oxygenates linoleyldimethylamine (LDMA) to give primarily 13(S)-hydroperoxy-9(Z),11(E)-octadecadienyldimethylamine. The oxygenation of LDMA occurs at about the same rate as LTMA at pH 7, but more slowly at pH 9. The results demonstrate that SBLO-1 will readily oxygenate substrates in which the carboxylate of linoleate is replaced with a cationic group, and the products of these reactions have the same stereo- and regiochemistry as the products obtained from fatty acid substrates.
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Affiliation(s)
- Lucas E Chohany
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
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Chechetkin I, Osipova E, Antsygina L, Gogolev Y, Grechkin A. Oxidation of glycerolipids by maize 9-lipoxygenase and its A562G mutant. Chem Phys Lipids 2011; 164:216-20. [DOI: 10.1016/j.chemphyslip.2011.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 12/30/2010] [Accepted: 01/19/2011] [Indexed: 01/03/2023]
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Zheng Y, Brash AR. On the role of molecular oxygen in lipoxygenase activation: comparison and contrast of epidermal lipoxygenase-3 with soybean lipoxygenase-1. J Biol Chem 2010; 285:39876-87. [PMID: 20923767 PMCID: PMC3000969 DOI: 10.1074/jbc.m110.180794] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 10/03/2010] [Indexed: 11/06/2022] Open
Abstract
The oxygenation of polyunsaturated fatty acids by lipoxygenases (LOX) is associated with a lag phase during which the resting ferrous enzyme is converted to the active ferric form by reaction with fatty acid hydroperoxide. Epidermal lipoxygenase-3 (eLOX3) is atypical in displaying hydroperoxide isomerase activity with fatty acid hydroperoxides through cycling of the ferrous enzyme. Yet eLOX3 is capable of dioxygenase activity, albeit with a long lag phase and need for high concentrations of hydroperoxide activator. Here, we show that higher O(2) concentration shortens the lag phase in eLOX3, although it reduces the rate of hydroperoxide consumption, effects also associated with an A451G mutation known to affect the disposition of molecular oxygen in the LOX active site. These observations are consistent with a role of O(2) in interrupting hydroperoxide isomerase cycling. Activation of eLOX3, A451G eLOX3, and soybean LOX-1 with 13-hydroperoxy-linoleic acid forms oxygenated end products, which we identified as 9R- and 9S-hydroperoxy-12S,13S-trans-epoxyoctadec-10E-enoic acids. We deduce that activation partly depends on reaction of O(2) with the intermediate of hydroperoxide cleavage, the epoxyallylic radical, giving an epoxyallylic peroxyl radical that does not further react with Fe(III)-OH; instead, it dissociates and leaves the enzyme in the activated free ferric state. eLOX3 differs from soybean LOX-1 in more tightly binding the epoxyallylic radical and having limited access to O(2) within the active site, leading to a deficiency in activation and a dominant hydroperoxide isomerase activity.
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Affiliation(s)
- Yuxiang Zheng
- From the Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Alan R. Brash
- From the Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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Ivanov I, Heydeck D, Hofheinz K, Roffeis J, O'Donnell VB, Kuhn H, Walther M. Molecular enzymology of lipoxygenases. Arch Biochem Biophys 2010; 503:161-74. [PMID: 20801095 DOI: 10.1016/j.abb.2010.08.016] [Citation(s) in RCA: 405] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/19/2010] [Accepted: 08/20/2010] [Indexed: 10/19/2022]
Abstract
Lipoxygenases (LOXs) are lipid peroxidizing enzymes, implicated in the pathogenesis of inflammatory and hyperproliferative diseases, which represent potential targets for pharmacological intervention. Although soybean LOX1 was discovered more than 60years ago, the structural biology of these enzymes was not studied until the mid 1990s. In 1993 the first crystal structure for a plant LOX was solved and following this protein biochemistry and molecular enzymology became major fields in LOX research. This review focuses on recent developments in molecular enzymology of LOXs and summarizes our current understanding of the structural basis of LOX catalysis. Various hypotheses explaining the reaction specificity of different isoforms are critically reviewed and their pros and cons briefly discussed. Moreover, we summarize the current knowledge of LOX evolution by profiling the existence of LOX-related genomic sequences in the three kingdoms of life. Such sequences are found in eukaryotes and bacteria but not in archaea. Although the biological role of LOXs in lower organisms is far from clear, sequence data suggests that this enzyme family might have evolved shortly after the appearance of atmospheric oxygen on earth.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry, University Medicine Berlin - Charité, Germany
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Active transition metal oxo and hydroxo moieties in nature's redox, enzymes and their synthetic models: Structure and reactivity relationships. Coord Chem Rev 2010. [DOI: 10.1016/j.ccr.2010.01.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Chechetkin IR, Osipova EV, Tarasova NB, Mukhitova FK, Hamberg M, Gogolev YV, Grechkin AN. Specificity of oxidation of linoleic acid homologs by plant lipoxygenases. BIOCHEMISTRY. BIOKHIMIIA 2009; 74:855-61. [PMID: 19817685 DOI: 10.1134/s0006297909080069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The lipoxygenase-catalyzed oxidation of linoleic acid homologs was studied. While the linoleic acid oxidation by maize 9-lipoxygenase (9-LO) specifically produced (9S)-hydroperoxide, the dioxygenation of (11Z,14Z)-eicosadienoic (20:2) and (13Z,16Z)-docosadienoic (22:2) acids by the same enzyme lacked regio- and stereospecificity. The oxidation of 20:2 and 22:2 by 9-LO afforded low yields of racemic 11-, 12-, 14-, and 15-hydroperoxides or 13- and 17-hydroperoxides, respectively. Soybean 13-lipoxygenase-1 (13-LO) specifically oxidized 20:2, 22:2, and linoleate into (omega6S)-hydroperoxides. Dioxygenation of (9Z,12Z)-hexadecadienoic acid (16:2) by both 9-LO and 13-LO occurred specifically, affording (9S)- and (13S)-hydroperoxides, respectively. The data are consistent with the "pocket theory of lipoxygenase catalysis" (i.e. with the penetration of a substrate into the active center with the methyl end first). Our findings also demonstrate that the distance between carboxyl group and double bonds substantially determines the positioning of substrates within the active site.
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Affiliation(s)
- I R Chechetkin
- Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, 420111, Russia.
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A Substrate Serves as a Hydrogen Atom Donor in the Enzyme-Initiated Catalytic Mechanism of Dual Positional Specific Maize Lipoxygenase-1. B KOREAN CHEM SOC 2009. [DOI: 10.5012/bkcs.2009.30.4.917] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Fiorucci S, Golebiowski J, Cabrol-Bass D, Antonczak S. Molecular simulations enlighten the binding mode of quercetin to lipoxygenase-3. Proteins 2009; 73:290-8. [PMID: 18655056 DOI: 10.1002/prot.22179] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Inhibition of lipoxygenases (LOXs) by flavonoid compounds is now well documented, but the description of the associated mechanism remains controversial due to a lack of information at the molecular level. For instance, X-ray determination of quercetin/LOX-3 system has led to a structure where the enzyme was cocrystallized with a degradation product of the substrate, which rendered the interpretation of the reported interactions between this flavonoid compound and the enzyme difficult. Molecular modeling simulations can in principle allow obtaining precious insights that could fill this lack of structural information. Thus, in this study, we have investigated various binding modes of quercetin to LOX-3 enzyme in order to understand the first step of the inhibition process, that is the association of the two entities. Molecular dynamics simulations and free energy calculations suggest that quercetin binds the metal center via its 3-hydroxychromone function. Moreover, enzyme/substrate interactions within the cavity impose steric hindrances to quercetin that may activate a direct dioxygen addition on the substrate.
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Affiliation(s)
- Sébastien Fiorucci
- Laboratoire de Chimie des Molécules Bioactives et des Arômes, UMR-CNRS 6001, Faculté des Sciences, Université de Nice Sophia Antipolis, 06108 Nice Cedex 2, France
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Aparoy P, Leela T, Reddy RN, Reddanna P. Computational analysis of R and S isoforms of 12-lipoxygenases: homology modeling and docking studies. J Mol Graph Model 2008; 27:744-50. [PMID: 19147381 DOI: 10.1016/j.jmgm.2008.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2008] [Revised: 11/18/2008] [Accepted: 11/19/2008] [Indexed: 11/19/2022]
Abstract
The present study is aimed at predicting human 12R-LOX structure by constructing a homology model. Based upon Blast results, rabbit reticulocyte 15-lipoxygenase 1LOX (protein data bank) was considered as a template for homology modeling. The 3D model was generated with Modeler in InsightII and further refined using AMBER. Further to understand the relationship of protein structure with stereo specificity, a comparative analysis of 12R-LOX model was done with that of 12S-LOX homology model to identify differences in the binding site topology and interacting residues. The large insertion of 31-aa seen in 12R-LOX is located beyond the N-terminal barrel and is accommodated on the outside of the protein without disruption of the overall tertiary structure. The 31-aa region includes SH3 domain binding PXXP motif, seven prolines and five arginines. The docking of the substrate, arachidonic acid was also performed. Our results show that the Gly441 and substrate orientation within the active site play an important role in stereo specificity of 12R-LOX.
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Affiliation(s)
- P Aparoy
- School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
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Boeglin WE, Itoh A, Zheng Y, Coffa G, Howe GA, Brash AR. Investigation of substrate binding and product stereochemistry issues in two linoleate 9-lipoxygenases. Lipids 2008; 43:979-87. [PMID: 18795358 PMCID: PMC4710486 DOI: 10.1007/s11745-008-3230-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 08/18/2008] [Indexed: 10/21/2022]
Abstract
Herein we characterize the Arabidopsis thaliana AtLOX1 and tomato (Solanum lycopersicum) LOXA proteins as linoleate 9S-lipoxygenases (9-LOX), and use the enzymes to test a model that predicts a relationship between substrate binding orientation and product stereochemistry. The cDNAs were heterologously expressed in E. coli and the proteins partially purified by nickel affinity chromatography using a N-terminal (His)(6)-tag. Both enzymes oxygenated linoleic acid almost exclusively to the 9S-hydroperoxide with turnover numbers of 300-400/s. AtLOX1 showed a broad range of activity over the range pH 5-9 (optimal at pH 6); tomato LOXA also showed optimal activity around pH 5-7 dropping off more sharply at pH 9. Site-directed mutagenesis of a conserved active site Ala (Ala562 in AtLOX1, Ala 564 in tomato LOXA, and typically conserved as Ala in S-LOX and Gly in R-LOX), revealed that substitution with Gly led to the production of a mixture of 9S- and 13R-hydroperoxyoctadecadienoic acids from linoleic acid. To follow up on earlier reports of 9-LOX metabolism of anandamide (van Zadelhoff et al. Biochem. Biophys. Res. Commun. 248:33-38, 1998), we also tested this substrate with the mutants, which produced predictable shifts in product profile, including a shift from the prominent 11S-hydroperoxy derivative of wild-type to include the 15R-hydroperoxide. These results conform to a model that predicts a head-first substrate binding orientation for 9S-LOX. We also found that linoleoyl-phosphatidylcholine is not a 9S-LOX substrate, which is consistent with this conclusion.
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Affiliation(s)
- William E Boeglin
- Department of Pharmacology, Vanderbilt University Medical Center, RRB Room 510, 23rd Ave at Pierce, Nashville, TN, 37232-6602, USA.
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Zheng Y, Boeglin WE, Schneider C, Brash AR. A 49-kDa mini-lipoxygenase from Anabaena sp. PCC 7120 retains catalytically complete functionality. J Biol Chem 2007; 283:5138-47. [PMID: 18070874 DOI: 10.1074/jbc.m705780200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Anabaena sp. PCC 7120 is one of the few prokaryotes harboring a lipoxygenase (LOX) gene. The sequence resides in an open reading frame encoding a fusion protein of a catalase-like hemoprotein with an unusually short LOX (approximately 49 kDa) at the C terminus. The recombinant mini-LOX contains a non-heme iron in the active site and is highly active with linoleic and alpha-linolenic acids (which occur naturally in Anabaena) giving the respective 9R-hydroperoxides, the mirror image of the 9S-LOX products of plants. Using stereospecifically labeled [11-(3)H]linoleic acids we show that reaction is catalyzed via a typical antarafacial relationship of initial hydrogen abstraction and oxygenation. The mini-LOX oxygenated C16/C18:2-phosphatidylcholine with 9R specificity, suggesting a "tail first" mode of fatty acid binding. Site-directed mutagenesis of an active site Ala (Ala215), typically conserved as Gly in R-LOX, revealed that substitution with Gly retained 9R specificity, whereas the larger Val substitution switched oxygenation to 13S, implying that Ala215 represents the functional equivalent of the Gly in other R-LOX. Metabolism studies using a synthetic fatty acid with extended double bond conjugation, 9E,11Z,14Z-20:3omega6, showed that the mini-LOX can control oxygenation two positions further along the fatty acid carbon chain. We conclude that the mini-LOX, despite lacking the beta-barrel domain and much additional sequence, is catalytically complete. Interestingly, animal and plant LOX, which undoubtedly share a common ancestor, are related in sequence only in the catalytic domain; it is possible that the prokaryotic LOX represents a common link and that the beta-barrel domain was then acquired independently in the animal and plant kingdoms.
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Affiliation(s)
- Yuxiang Zheng
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-6602, USA
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50
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Schneider C, Pratt DA, Porter NA, Brash AR. Control of oxygenation in lipoxygenase and cyclooxygenase catalysis. ACTA ACUST UNITED AC 2007; 14:473-88. [PMID: 17524979 PMCID: PMC2692746 DOI: 10.1016/j.chembiol.2007.04.007] [Citation(s) in RCA: 222] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 04/03/2007] [Accepted: 04/10/2007] [Indexed: 12/16/2022]
Abstract
Lipoxygenases (LOX) and cyclooxygenases (COX) react an achiral polyunsaturated fatty acid with oxygen to form a chiral peroxide product of high regio- and stereochemical purity. Both enzymes employ free radical chemistry reminiscent of hydrocarbon autoxidation but execute efficient control during catalysis to form a specific product over the multitude of isomers found in the nonenzymatic reaction. Exactly how both dioxygenases achieve this positional and stereo control is far from clear. We present four mechanistic models, not mutually exclusive, that could account for the specific reactions of molecular oxygen with a fatty acid in the LOX or COX active site.
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Affiliation(s)
- Claus Schneider
- Department of Pharmacology, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, U.S.A
| | - Derek A. Pratt
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, U.S.A
- Department of Chemistry, Queen’s University, Kingston, Ontario, Canada K7L 3N6
| | - Ned A. Porter
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, U.S.A
| | - Alan R. Brash
- Department of Pharmacology, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, U.S.A
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